JPS5935998Y2 - High frequency heating device - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a means for matching the magnetron and the heating chamber in a high-frequency heating device.

In high-frequency heating devices, so-called microwave ovens, creating a symmetrical pattern of electric field strength within the heating chamber is an important factor in eliminating uneven heating.

That is, when a plurality of loads are placed in the heating chamber at the same time, the above-mentioned symmetry of electric field strength is extremely effective in order for the temperature of all of them to rise uniformly.

In addition, in the type of microwave oven in which the Magne I-ron is directly connected to the top of the heating chamber, the Magne-I-ron is placed in the center of the top of the heating chamber, and one coaxial or multiple stirrer at symmetrical positions is installed. A so-called central feeding system equipped with a fan has already been widely put into practical use.

Even with waveguides, a type of T-branch or L-branch waveguide has recently been proposed in which the power supply opening is provided at the center of the upper or lower surface of the heating chamber and the opening protrudes into the refrigerator. Attempts are already being made to put it into practical use.

FIG. 1 is a cross-sectional view of a device equipped with a T-branch waveguide, showing one example thereof.

With such a branched waveguide, central power feeding is possible even in waveguide power feeding, but it is possible to connect the heating chamber 2 from the -plane protruding opening 1.
The change in the impedance of the space leading to the heating was rapid, reflected waves were likely to occur, and mismatching between the heating chamber 2 and the magnetron 3 was likely to occur.

2 in FIG. 2 is a Rieke diagram showing the operating point of such mismatching open, and even if the waveguide dimensions are changed, the waveguide simply moves on the same constant wave as shown by the arrow.

Further, since the microwaves went straight to the bottom of the opening (arrow), the stirring effect of the stirrer fan 4 was insufficient.

In addition, the magnetron was easily affected by the load side, and the operating point varied greatly depending on the amount and position of the load, making it difficult to obtain a stable high-frequency output and prone to unstable oscillations such as moding.

Therefore, the present invention is to realize a power supply structure that eliminates the above-mentioned drawbacks of a microwave oven using a branched waveguide.An embodiment of the present invention will be described below with reference to the drawings.

In FIGS. 3 and 4, the waveguide 5 communicates with a protruding waveguide 6, whose open end 7 is bent in the longitudinal direction as shown.

Further, the opening position is at the center of the upper surface of the heating chamber, and the stirrer fan 4 is also formed in a symmetrical shape.

With this configuration, the microwaves are distributed to the left and right as shown in the figure (arrows).

This is because the opening tip 7 and the horizontal member of the stirrer fan 4 equivalently form an H branch path.

Therefore, a sudden change in impedance at the aperture 1 can be avoided, and operation in a region where the standing wave ratio is small, as shown by ■ in FIG. 2, can be realized.

Furthermore, since the microwaves travel in the direction of the blades of the stirrer fan, the stirring effect is significantly improved, and not only the symmetrical heating of the plurality of foods 8 but also the temperature distribution inside each food can be improved.

That is, so-called fine-grained heating becomes possible.

9 is a saucer, and 10 is a partition plate.

In this embodiment, the waveguide is L-branched, but it goes without saying that it can also be applied to a T-branch as shown in FIG. 1, and furthermore, it can be applied to power feeding from below.

Further, although the opening tip 7 is bent, it is also possible to use a separate structure with spora I, welding, or tightening with screws.

Furthermore, it may be provided not only in the longitudinal direction but also in the lateral direction.

Although it is most effective to make the H branch path by making the bending angle approximately right angle and having the two sides parallel to the stirrer fan facing each other, even if you choose an angle other than right angle, the bending angle will be much lower than the conventional example. It is easy to match.

The tip of the opening is shaped like a half-moon in this example, but this is to ensure the largest possible area in consideration of the rotation of the stirrer fan. Obtainable.

As described above, according to the present invention, a sudden change in impedance from the power supply opening to the heating chamber can be avoided, and matching can be easily achieved.

Therefore, stable oscillation can be obtained at an efficient operating point, and large high-frequency output can be efficiently and stably extracted.

In addition, the microwaves travel toward the blades of the stirrer fan, are stirred, and then radiated from the surroundings, which not only creates symmetry in the electric field within the heating chamber, but also achieves so-called fine-grained heating with a good stirring effect. can.

In addition, the distance between the magnetron antenna and the load is increased, making it less susceptible to the influence of the load side (load amount, position), stabilizing the high frequency output characteristics due to the load, and eliminating unstable oscillation.

In addition, the bent portion at the tip of the opening serves as reinforcement in the longitudinal direction, stabilizing the opening dimension, which has a large effect on the standing wave pattern within the heating chamber.

In addition, since the bent corner is located at the opening where the electric field concentration is most intense, sparks are much less likely to occur at this part compared to the conventional example where the cut end is located.

[Brief explanation of the drawing]

Figure 1 is a new view of a high-frequency heating device showing a conventional example;
The figure is a case diagram showing operating points, FIG. 3 is a front new view of a high-frequency heating device showing an embodiment of the present invention, and FIG. 4 is a view of the opening seen from below. 1... Opening, 4... Stirrer fan,
6... Protruding waveguide, 7... Opening tip.

Claims (1)

[Scope of utility model registration request] A waveguide having an opening in the wall surface of the heating chamber, a protruding waveguide that is substantially perpendicular to the waveguide and provided in the opening and protruding into the heating chamber, and an abbreviated letter extending from the tip of the protruding portion to the outside of the opening. A high-frequency heating device consisting of a stirrer fan that rotates around a protruding waveguide and has an opening tip that is bent into an arc shape and has a conductor portion located opposite to the opening tip.